src/file-manifest.cpp

/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/**
* Copyright (c) 2016 Regents of the University of California.
*
* This file is part of the nTorrent codebase.
*
* nTorrent is free software: you can redistribute it and/or modify it under the
* terms of the GNU Lesser General Public License as published by the Free Software
* Foundation, either version 3 of the License, or (at your option) any later version.
*
* nTorrent is distributed in the hope that it will be useful, but WITHOUT ANY
* WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
* PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.
*
* You should have received copies of the GNU General Public License and GNU Lesser
* General Public License along with nTorrent, e.g., in COPYING.md file. If not, see
* <http://www.gnu.org/licenses/>.
*
* See AUTHORS for complete list of nTorrent authors and contributors.
*/
#include "file-manifest.hpp"

#include <boost/assert.hpp>
#include <boost/range/adaptors.hpp>
#include <boost/throw_exception.hpp>

using std::vector;

namespace ndn {
namespace ntorrent {

BOOST_CONCEPT_ASSERT((boost::EqualityComparable<FileManifest>));
BOOST_CONCEPT_ASSERT((WireEncodable<FileManifest>));
BOOST_CONCEPT_ASSERT((WireDecodable<FileManifest>));
static_assert(std::is_base_of<Data::Error, FileManifest::Error>::value,
                "FileManifest::Error should inherit from Data::Error");

void
FileManifest::wireDecode(const Block& wire)
{
  Data::wireDecode(wire);
  this->decodeContent();
}

const Block&
FileManifest::wireEncode()
{
  encodeContent();
  return Data::wireEncode();
}

template<ndn::encoding::Tag TAG>
size_t
FileManifest::encodeContent(ndn::EncodingImpl<TAG>& encoder) const {
  // FileManifestName ::= NAME-TYPE TLV-LENGTH
  //                  Name

  // ManifestContent ::= CONTENT-TYPE TLV-LENGTH
  //                 DataPacketName*
  //                 CatalogPrefix
  //                 DataPacketSize
  //                 FileManifestPtr?

  // DataPacketName ::= NAME-TYPE TLV-LENGTH
  //                Name

  // CatalogPrefix ::= NAME-TYPE TLV-LENGTH
  //               Name

  // DataPacketSize ::= CONTENT-TYPE TLV-LENGTH
  //                nonNegativeInteger

  // FileManifestPtr ::= NAME-TYPE TLV-LENGTH
  //                 Name

  size_t totalLength = 0;

  vector<Name> suffixCatalog;
  suffixCatalog.reserve(m_catalog.size());
  for (auto name: m_catalog) {
    if (!m_catalogPrefix.isPrefixOf(name)) {
      BOOST_THROW_EXCEPTION(Error(name.toUri() + "does not have the prefix"
                                               + m_catalogPrefix.toUri()));
    }
    name = name.getSubName(m_catalogPrefix.size());
    if (name.empty()) {
      BOOST_THROW_EXCEPTION(Error("Manifest cannot include empty string"));
    }
    suffixCatalog.push_back(name);
  }

  for (const auto& name : suffixCatalog |  boost::adaptors::reversed) {
    totalLength += name.wireEncode(encoder);
  }

  totalLength += m_catalogPrefix.wireEncode(encoder);

  totalLength += prependNonNegativeIntegerBlock(encoder, tlv::Content, m_dataPacketSize);

  if (nullptr != m_submanifestPtr) {
    totalLength += m_submanifestPtr->wireEncode(encoder);
  }

  totalLength += encoder.prependVarNumber(totalLength);
  totalLength += encoder.prependVarNumber(tlv::Content);
  return totalLength;

}

// MANIPULATORS
void
FileManifest::push_back(const Name& name)
{
  BOOST_ASSERT(name != m_catalogPrefix);
  BOOST_ASSERT(m_catalogPrefix.isPrefixOf(name));
  m_catalog.push_back(name);
}

bool
FileManifest::remove(const ndn::Name& name) {
  auto it = std::find(m_catalog.begin(), m_catalog.end(), name);
  if (m_catalog.end() == it) {
    return false;
  }
  m_catalog.erase(it);
  return true;
}

void FileManifest::encodeContent() {
  // Name
  //     <file_name>/ImplicitDigest
  // Content
  //     MetaData
  //     DataPtr*
  //     ManifestPointer?
  //
  // DataPtr := HashValue
  // ManifestPtr := HashValue
  // HashValue   := OCTET[32]

  // MetaData    := Property*
  // Property    := DataSize | Signature
  onChanged();

  EncodingEstimator estimator;
  size_t estimatedSize = encodeContent(estimator);

  EncodingBuffer buffer(estimatedSize, 0);
  encodeContent(buffer);

  setContentType(tlv::ContentType_Blob);
  setContent(buffer.block());
}

void
FileManifest::decodeContent() {
  // ManifestContent ::= CONTENT-TYPE TLV-LENGTH
  //                 DataPacketName*
  //                 CatalogPrefix
  //                 DataPacketSize
  //                 FileManifestPtr?


  // DataPacketName ::= NAME-TYPE TLV-LENGTH
  //                Name

  // CatalogPrefix ::= NAME-TYPE TLV-LENGTH
  //               Name

  // DataPacketSize ::= CONTENT-TYPE TLV-LENGTH
  //                nonNegativeInteger

  // FileManifestPtr ::= NAME-TYPE TLV-LENGTH
  //                 Name

  if (getContentType() != tlv::ContentType_Blob) {
    BOOST_THROW_EXCEPTION(Error("Expected Content Type Blob"));
  }

  const Block& content = Data::getContent();
  content.parse();

  auto element = content.elements_begin();

  if (content.elements_end() == element) {
    BOOST_THROW_EXCEPTION(Error("FileManifest with empty content"));
  }

  element->parse();
  Name name(*element);

  // Submanifest ptr
  if (!name.empty()) {
    m_submanifestPtr = std::make_shared<Name>(name);
    ++element;
  }

  // DataPacketSize
  m_dataPacketSize = readNonNegativeInteger(*element);
  ++element;

  // CatalogPrefix
  m_catalogPrefix = Name(*element);
  element++;

  // Catalog
  m_catalog.clear();
  for (; element != content.elements_end(); ++element) {
    element->parse();
    name = m_catalogPrefix;
    name.append(Name(*element));
    if (name == m_catalogPrefix) {
      BOOST_THROW_EXCEPTION(Error("Empty name included in a FileManifest"));
    }
    push_back(name);
  }
}

bool operator==(const FileManifest& lhs, const FileManifest& rhs) {
  return lhs.name()             == rhs.name()
      && lhs.data_packet_size() == rhs.data_packet_size()
      && (lhs.submanifest_ptr() == rhs.submanifest_ptr() /* shallow  equality */
         || ( nullptr != lhs.submanifest_ptr()
           && nullptr != rhs.submanifest_ptr()
           && *rhs.submanifest_ptr() == *lhs.submanifest_ptr()
         )
      )
      && lhs.catalog()          == rhs.catalog();
}

bool operator!=(const FileManifest& lhs, const FileManifest& rhs) {
  return lhs.name()             != rhs.name()
      || lhs.data_packet_size() != rhs.data_packet_size()
      || (lhs.submanifest_ptr() != rhs.submanifest_ptr() /* shallow  equality */
         && (nullptr == lhs.submanifest_ptr()
         || nullptr == rhs.submanifest_ptr()
         || *rhs.submanifest_ptr() != *lhs.submanifest_ptr()
        )
      )
      || lhs.catalog()          != rhs.catalog();
}

}  // end ntorrent
}  // end ndn